The invention generally relates to clamps. More particularly, the invention relates to clamps for securing rolls of paper (commonly referred to in the trade as “logs”) during sawing processes.
Many types of paper are produced in logs for ease of manufacture. As used herein and in the appended claims, the term “log” is meant to include rolls of paper products such as napkins, paper towels, facial tissue, toilet tissue, newsprint, and the like. Also, because the present invention is not limited to rolls of paper products, the term “log” is meant to include rolls of products which are made from other materials including without limitation cellophane, plastic sheeting, and other synthetic materials, fabric, woven, and non-woven textiles and cloth, foil, etc., regardless of product porosity, density, and dimensions. These logs must typically be sawn into shorter rolls more readily used by consumers. Automating the sawing process is necessary to achieve satisfactory production rates. Typically, automated sawing processes have utilized a reciprocating or orbital radial or band saw in combination with a stationary log clamp.
Bias cutting and inadequate clamping of the log reduce the yield of prior art sawing processes. Tremendous pressure is placed on the saw blade as it cuts into the log because the saw blade is normally toothless to avoid shredding the log. Thus, this cutting process often requires greater force to shear the log than a process involving a blade with teeth, increasing bias cutting and log core crushing problems.
Prior art clamps often secure a log using elastic straps or grippers during the sawing process, and can often be adjusted for varying diameters. However, these clamps may allow slight movement during the sawing process, especially for logs of large diameter and heavy density. A clamp should hold the log stable when the blade applies large forces while penetrating the log.
Various clamping methods and apparatus have been used in the past. Nevertheless, a new clamping method and apparatus that provides enhanced performance and results in improved product quality would be welcomed by those in the art.